Itunes version 12.8.3.1 wont connect to iphone 8 running ios 15
I have an iMac running iOS 10.13.6 with iTunes 12.8.3.1, there are no updates available for either. My iPhone 8, running iOS 15.2 won't connect to iTunes "iTunes could not connect to this iPhone. Could not allocate a resource".
iPhone opens up photos when connected by usb, so usb cable seems ok.
Unable to synch, backup or restore, move music to iPhone or carry out any iTunes function.
This has been the case for several months now so isn't due to any recent upgrades.
Help appreciated.
iMac, macOS 10.13